ISS¶
Inner-Shell Spectroscopy at NSLS-II, beamline 8-ID: X-ray absorption (EXAFS) by a trajectory energy fly-scan, plus X-ray emission (XES) and high-energy-resolution fluorescence detection (HERFD) on two crystal emission spectrometers. This page describes how CORA would model and run ISS; the model is reverse-engineered from public configuration, not yet confirmed by ISS staff.
| Property | Value |
|---|---|
| Asset | ISS (root Asset, tier = Unit, parent_id = None) |
| Facility | NSLS-II (bound via facility_code = "nsls2", FacilityKind = Site) |
| Sector | Sector 8 (PV namespace XF:08ID*) |
| Institution | Brookhaven National Laboratory (context; not modeled as an Asset or Facility) |
| Status | Reverse-engineered from public config (design-phase scaffold) |
| Source | 8-ID in-vacuum undulator on the NSLS-II 3 GeV ring (energy driven through the HHM trajectory) |
How CORA would land on ISS
These pages describe how CORA would model, govern, and conduct ISS, the thirteenth NSLS-II beamline after FXI, HXN, BMM, SRX, SIX, CHX, CSX, XPD, ESM, SMI, IXS, and SST. They are not a survey of the beamline's current software. The hardware facts (devices, EPICS PVs, axes) are read from public NSLS-II open source (the NSLS2/iss-profile-collection bluesky / ophyd startup files) and verified against it; undulator parameters, crystal cuts, and physical positions are not in it, so they, and every read value, are carried confirm until ISS staff verify them (Open questions). This is a design-phase scaffold: the descriptor and these docs, with scenarios deferred.
The defining shape: the energy sweep is the measurement¶
ISS is CORA's first dedicated X-ray absorption spectroscopy beamline, and its defining shape is the trajectory energy fly-scan: the high-heat-load monochromator follows a pre-computed Bragg-angle look-up table on a Delta-Tau motion controller while the ion-chamber and fluorescence detectors stream against an encoder. The energy sweep is the EXAFS measurement, the textbook case for the energy_scan Capability the catalog has anticipated since BMM (it stays deferred, ENERGY-1; ISS is a further consumer that strengthens it). Alongside absorption, ISS reads X-ray emission: two crystal emission spectrometers (a back-scattering Johann and a wavelength-dispersive von Hamos) measure XES and HERFD. Those spectrometers are the value to CORA: they bring the EmissionSpectrometer family to its second sighting (after LCLS-MFX's von Hamos), which GRADUATED it into the catalog. Every other device on ISS reuses an existing catalog Family.
The beamline¶
Along the beam, in order:
- Source: the 8-ID undulator, the front-end slit and shutters, then the optics, the high-heat-load trajectory monochromator and the high-resolution monochromator, the collimating and focusing mirrors, the harmonic-rejection mirror, the filter box, and the slits.
- Sample: the sample stage and goniometer, the energy-calibration reference foil wheel, and the thermal environment.
- Detector: the transmission / fluorescence ion chambers, the silicon-drift fluorescence detector, the area detector, and the Johann and von Hamos crystal emission spectrometers.
Cutting across all three:
- Controls: the trajectory fly-scan, the analog pizza box readout, and the motion controllers.
The cross-cutting reference view is the Inventory.
Techniques¶
Techniques: the absorption (EXAFS) and emission (XES / HERFD) techniques ISS runs, and why their Method scope stays pending.
Governance¶
Governance: who may act at ISS and the trust shape CORA applies; CORA brings its own per-Actor authority.
Model¶
Model: the developer's by-kind index into where each CORA aggregate's ISS content lives, and the EmissionSpectrometer graduation it earned.